Customize the Sign Up Source Property for a Form

Overview

When growing your email list, it's a best practice to ensure that all new signups are funneled to the same newsletter list, regardless of whether they signed up on your website, via a pop-up, etc. Because of this, we recommend tagging each signup form on your site with a unique $source property. This will allow you to isolate and track activity from each different signup method.

The $source property (with the $ as a prefix) is a special Klaviyo property used to represent "form signup source." This breakdown can be viewed in the List Growth Report for a particular list.

Keep in mind that someone can only join a given list once. This means if you have various lead generation tools on your site and expect that people might want to sign up for more than one, you will have to create different lists for each. You can then create a "master list" using the segment builder.

Klaviyo's Default $source Property

Klaviyo will automatically assign all list subscribers a $source property that reflects how the person was added your list. When someone unsubscribes, we will also track how he/she unsubscribed.

While it is possible to customize a given form's $source value (see below), we will otherwise track and use the following default values:

Default Subscribe Source Values

Unknown: Source non-identifiable

Modal: Added via a pop-up form

Fly Out: Added via a fly out form

Embedded Form: Added via an embedded form

Subscribe Page: Added via a subscribe page

Klaviyo UI: Added via Quick Add or via upload from CSV File

Integration: Added via opting in through an integration

API: Added to a list via the Klaviyo API

Default Unsubscribe Source Values

Unknown: Source non-identifiable

Klaviyo UI: Manually cleaned/removed from the list

Subscribe Page: Unsubscribed via an unsubscribe page

Integration: Unsubscribed via opting out through an integration

API: Unsubscribed from a list via the Klaviyo API

Customizing a Form's Sign Up Source

If you want to customize the $source property for a form, you can do this by making a small adjustment in your form's code.

To customize the signup source for a fly out, modal, or embedded form, create a $source property in an extra_properties dictionary.

Before you add this extra_properties dictionary, you will see this below your main form code: